The invention relates to a combinatorial process for performing a plurality of catalytic chemical reactions.
Developments in combinatorial chemistry have largely concentrated on the synthesis of chemical compounds. For example, U.S. Pat. Nos. 5,612,002 and 5,766,556 disclose a method and apparatus for multiple simultaneous synthesis of compounds. WO 97/30784-A1 discloses a microreactor for the synthesis of chemical compounds. Akporiaye, D. E.; Dahl, I. M.; Karlsson, A.; Wendelbo, R. Angew Chem. Int. Ed. 1998, 37, 609-611 disclose a combinatorial approach to the hydrothermal synthesis of zeolites, see also WO 98/36826. Other examples include U.S. Pat. Nos. 5,609,826, 5,792,431, 5,746,982, and 5,785,927, and WO 96/11878-A1.
More recently, combinatorial chemistry approaches have been applied to catalyst testing to try to expedite the testing process. For example, WO 97/32208-A1 teaches placing different catalysts in a multicell holder. The reaction occurring in each cell of the holder is measured to determine the activity of the catalysts by observing the heat liberated or absorbed by the respective formulation during the course of the reaction, and/or analyzing the products or reactants. Thermal imaging had been used as part of other combinatorial chemistry approaches to catalyst testing; see Holzwarth, A.; Schmodt, H.; Maier, W. F. Angew. Chem. Int. Ed., 1998, 37, 2644-2647, and Bein, T. Angew. Chem. Int. Ed., 1999, 38, 323-326. Thermal imaging may be a tool to learn some semi-quantitative information regarding the activity of the catalyst, but it provides no indication as to the selectivity of the catalyst.
Some attempts to acquire information as to the reaction products in rapid-throughput catalyst testing are described in Senkam, S. M. Nature July 1998, 384(23), 350-353 where laser-induced resonance-enhanced multiphoton ionization is used to analyze a gas flow from each of the fixed catalyst sites. Similarly, Cong, P.; Doolen, R. D.; Fan, Q.; Giaquinta, D. M.; Guan, S.; McFarland, E. W.; Poojary, D. M.; Self, K.; Turner, H. W.; Weinberg, W. H. Angew Chem. Int. Ed. 1999, 38, 484-488 teaches using a probe with concentric tubing for gas delivery/removal and sampling. Only the fixed bed of catalyst being tested is exposed to the reactant stream, with the excess reactants being removed via vacuum. The single fixed bed of catalyst being tested is heated and the gas mixture directly above the catalyst is sampled and sent to a mass spectrometer.
Combinatorial chemistry has been applied to evaluate the activity of catalysts. Some applications have focused on determining the relative activity of catalysts in a library; see Klien, J.; Lehmann, C. W.; Schmidt, H.; Maier, W. F. Angew Chem. Int. Ed. 1998, 37, 3369-3372; Taylor, S. J.; Morken, J. P. Science, April 1998, 280(10), 267-270; and WO 99/34206-A1. Some applications have broadened the information sought to include the selectivity of catalysts. WO 99/19724-A1 discloses screening for activities and selectivities of catalyst libraries having addressable test sites by contacting potential catalysts at the test sites with reactant streams forming product plumes. The product plumes are screened by passing a radiation beam of an energy level to promote photoions and photoelectrons which are detected by microelectrode collection. WO 98/07026-A1 discloses miniaturized reactors where the effluent is analyzed during the reaction time using spectroscopic analysis.
Some commercial processes have operated using multiple parallel reactors where the products of all of the reactors are combined into a single product stream; see U.S. Pat. No. 5,304,354 and U.S. Pat. No. 5,489,726.
Applicants have developed a combinatorial process particularly suited for the evaluation of catalysts. Multiple catalytic chemical reactions are conducted in parallel with the resulting reaction mixtures being analyzed. The parallel reactions and the analyses provide a means for the simultaneous evaluation of multiple catalysts or mixtures of catalysts.
The invention is a combinatorial process for simultaneously conducting multiple catalytic chemical reactions in parallel. The process begins with containing at least one catalyst in the reaction zones of a plurality of reactors, each reactor having a reactor insert placed within a sleeve and inserted into a well, the reaction zone of each reactor being formed between a fluid permeable structure spanning the cross-section of the sleeve and a fluid permeable end of the corresponding reactor insert. A fluid reactant is flowed through a first conduit of each reactor into at least one channel formed by the interior surface of the well and the external surface of the corresponding sleeve into a chamber of each reactor formed by a closed end of the well and the fluid permeable structure attached to the corresponding sleeve. In each reactor, the fluid reactant is flowed from the chamber through the fluid permeable structure spanning the cross-section of the sleeve and into the reaction zone where it is contacted with the catalyst contained in the reaction zone to form an effluent. The effluent is flowed through the fluid permeable portion of the reactor insert and into a second fluid conduit to remove the effluent from the reactor. The effluents from the plurality of reactors are analyzed.
In another specific embodiment of the invention, at least one catalyst is again contained in the reaction zones of a plurality of reactors, where each reactor has a reactor insert placed within a sleeve and inserted into a well, with the reaction zone of each reactor being formed between a fluid permeable structure spanning the cross-section of the sleeve and a fluid permeable end of the corresponding reactor insert. Fluid reactant is flowed through a first conduit of each reactor and through the fluid permeable portion of the reactor insert into the reaction zone of each reactor to contact the catalyst contained in the reaction zone and to form an effluent. The effluent is flowed through the fluid permeable portion structure spanning the cross-section of the sleeve and into at least one channel formed by the interior surface of the well and the external surface of the corresponding sleeve into a second fluid conduit to remove the effluent from the reactor. The effluents from the plurality of reactors are analyzed.
In yet another specific embodiment of the invention, the process begins with providing a plurality of reactors, with the preferred reactor being as follows. Each reactor has a well having an open end and a closed end and a first seal retained by the open end of the well. Each reactor also has a sleeve having a top end and a bottom end. The bottom end of the sleeve is inserted within the open end of the well. A fluid permeable structure is attached to the sleeve and spans the cross-section of the sleeve thereby defining a chamber between the closed end of the well and the fluid permeable structure attached to the sleeve. Each reactor also has a reactor insert having a fluid permeable end and a top end containing a first and a second fluid conduit. The fluid permeable end of the reactor is inserted within the open end of the sleeve. The top end of the reactor insert is engaged with the first seal. The first fluid conduit is in fluid communication with the chamber; and the second fluid conduit is in fluid communication with the bottom end of the reactor insert. A second seal retained by the reactor insert is engaged with the sleeve.
The combinatorial process continues with containing catalyst in each reaction zone; flowing fluid reactant through each first fluid conduit, each chamber, and through each fluid permeable structure attached to the sleeve and into each reaction zone to contact the catalyst therein and form reaction mixtures; flowing the effluents through each fluid permeable end of each reactor insert and removing the effluents through each second fluid conduit; and analyzing the effluents. The flow rate may be controlled so that the catalyst in the reaction zones is in a fluidized bed mode or a fixed bed mode.
In still another specific embodiment of the invention, the plurality of preferred reactors is as described above, but the fluid flow of reactant is reversed. Specifically, the process continues with containing catalyst in the reaction zone; flowing fluid reactant through the second fluid conduit, through the fluid permeable end of the reaction insert and into the reaction zone to contact the catalyst and form an effluent; flowing the effluent through the fluid permeable structure attached to the sleeve, through the chamber and removing the effluent through the first fluid conduit; and analyzing the effluent.